Update README.md

Update grammar
add Dockerfile
Correct some lexer errors
move Dockerfile to root
Merge pull request #4 from chancancode/patch-1

Correct some lexer errors
Merge pull request #3 from artintal/master

Update grammar in README.md
should update copyright year in LICENSE file; fix #7

the year of README.md and LICENSE should be consistent. the software is
related to the magazine article of 2015 issue of the (Japanese) programming
magazine.
Merge pull request #5 from proppy/dockerfile

add Dockerfile
update README.md for software requirement
Fix typo in README.md
Merge pull request #8 from suzukaze/fix-typo

Fix typo in README.md
update README.md for consistent spacing; ref #6
add true/false/nil to the syntax
Use system default compiler instead of unconditionally using gcc. Now works on FreeBSD too
add "How to contribute" to README.md; close #9
Merge pull request #10 from JuEeHa/master

Use system default compiler instead of unconditionally using gcc (FreeBSD compatibility)
use bison -y instead of plain yacc, since streem uses bison extension
place streem excutable to bin directory
avoid backticks, quote string, don't fail if dir exists
Merge pull request #14 from marado/master

avoid backticks, quote string, don't fail if dir exists